Risque details are emerging in a US court as testimony begins in the trial of an insurance businessman accused of helping a Zumba instructor engage in prostitution in a quaint Maine village.

A landlord who rented office space to the Zumba teacher testified he became suspicious when tenants heard "groaning and moaning".

A pizza shop manager told a jury that the woman disrobed in front of him during a delivery.

The witnesses testified in the trial of Mark Strong, who is charged with 13 counts of helping Alexis Wright engage in prostitution.

Wright, 30, is accused of engaging in prostitution at the dance studio, at an office across the street and at her own home. Authorities have said she made video recordings of clients without their knowledge. She will be tried later.

The case has generated attention because of the size of the alleged operation and its setting - a seaside village near Kennebunkport, home of the summer compound of former President George Bush Snr and his family.

A lawyer who has seen Wright's alleged client list says it includes more than 150 names.

Christopher West, a landlord who rented office space to Wright, testified that he began receiving complaints from other tenants within a two weeks. He testified about loud music, moaning, groaning and laughter coming from the office.

He became suspicious when he saw men coming and going. He told police he intended to evict her but was asked to hold off because of a police investigation.

After police executed a search warrant, he said he discovered a box of adult toys, a bin of used condoms and baby wipes, and a massage table. An agent seized two video cameras, including one that was hidden.

Dan Racaniello, manager of a pizza shop next to the studio, testified that when he delivered spaghetti and meatballs with garlic bread, Wright came to the door wearing only a towel, which she dropped to reveal she was naked.

She paid US$40 for the US$8 meal and told him to keep the change.

"She fussed around with her wallet and off goes the towel. I felt awkward," said Racaniello, who left her apartment stunned both by the nudity and a generous tip, saying, "It made my day."

Both Strong and Wright have pleaded not guilty.

Strong helped Wright launch her Pura Vida dance-fitness studio by co-signing for her lease and lending money with commercial notes that were repaid with interest.